1. Field of the Invention
The invention relates to an analytical technique of a chip, and more particularly, to a method for detecting an electrical defect of contact/via plugs.
2. Description of Related Art
Die to die inspection is widely used inspection methodology, this method is to capture the defective optical, SEM or patch image in inspecting die and then compare with the other die reference image at the exactly same location in real time. However, as the technology node shrinks to 40 nm and beyond, it is hard to use large inspection field to inspect the tiny defects in electron beam (E-beam) inspection.
The E-Beam inspection (EBI) tool is currently used to obtain the image of the surface structure of a chip. Voltage contrast (VC) inspection in EBI is widely utilized to capture electrical defects of contact/via plugs. The monitoring of VC variations in the via plugs are more complicated than that of contact plugs because the via plugs layout structure connecting with different pitches, length metal lines and metallic layers.
Therefore, it needs to develop method for the technology node shrinkage.